The CIA (and its predecessors the OSS/COI formed by British intelligence) has had a long history of manipulating Hoover and the FBI with false or skewed information - particularly in relation to 'the communism threat'. This particular document falls under that category because it has now been proven that the whole 'brainwashing' threat as supposedly a communist invention was completely false and merely used to gain funding and a credible reason to continue human experimentation begun in Nazi Germany during WWII.
Please see these for further information about the brainwashing lie - post #1 and post #2.
It is of note that within 2 months of this rather obvious prompting document sent by Dulles, Hoover began creating the infamous COINTELPRO program. It's main target was "the Communist Party."